在 2023/6/6 22:37, Zhihao Cheng 写道:
在 2023/6/6 0:50, Matthew Wilcox (Oracle) 写道:
Hi,
This is a simplistic conversion to separate out any effects of
no longer having a writepage method.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/ubifs/file.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 979ab1d9d0c3..8bb4cb9d528f 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1003,8 +1003,10 @@ static int do_writepage(struct page *page, int
len)
* on the page lock and it would not write the truncated inode node
to the
* journal before we have finished.
*/
-static int ubifs_writepage(struct page *page, struct
writeback_control *wbc)
+static int ubifs_writepage(struct folio *folio, struct
writeback_control *wbc,
+ void *data)
{
+ struct page *page = &folio->page;
struct inode *inode = page->mapping->host;
struct ubifs_info *c = inode->i_sb->s_fs_info;
struct ubifs_inode *ui = ubifs_inode(inode);
@@ -1076,6 +1078,12 @@ static int ubifs_writepage(struct page *page,
struct writeback_control *wbc)
return err;
}
+static int ubifs_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ return write_cache_pages(mapping, wbc, ubifs_writepage, NULL);
+}
+
There is a small difference.
before patch applied:
do_writepages -> write_cache_pages -> writepage_cb:
ubifs_writepage
mapping_set_error(mapping, ret)
So, we can get error returned from errseq_check_and_advance in syncfs
syscall if ubifs_writepage occurs EIO.
after patch applied:
do_writepages -> ubifs_writepages -> write_cache_pages ->
ubifs_writepage, mapping won't be set error if ubifs_writepage failed.
Unfortunately, ubifs is not a block filesystem, so
sync_filesystem->sync_blockdev_nowait will return 0. Finally, syncfs
syscall will return 0.
I think we can add mapping_set_error in error branch of ubifs_writepage
to solve it.
BTW, I notice that shrink_folio_list -> pageout will try to shrink page
by writepage method, if we remove '->writepage', the dirty page won't be
shrinked in that way?
/**
* do_attr_changes - change inode attributes.
* @inode: inode to change attributes for
@@ -1636,7 +1644,7 @@ static int ubifs_symlink_getattr(struct
mnt_idmap *idmap,
const struct address_space_operations ubifs_file_address_operations = {
.read_folio = ubifs_read_folio,
- .writepage = ubifs_writepage,
+ .writepages = ubifs_writepages,
.write_begin = ubifs_write_begin,
.write_end = ubifs_write_end,
.invalidate_folio = ubifs_invalidate_folio,
.
